Each year the quantity of land in America that can be used to produce food is diminished by urban spread and changing weather patterns. This problem is compounded by the fact that the number of people in the world who need farm-grown food increases. It is therefore absolutely imperative that maximum and efficient use be made of all our remaining farming land. One method of establishing such efficient use is the age-old water irrigation of arid land to render the same crop producing land; however, some systems of irrigation require large capital expenditures and are dependent upon the flow of water from a natural source. This problem can be eliminated by artifically constructing irrigation systems via man-made wells, pipes, valves, etc. In order to maximize the efficiency of artifical irrigation systems, it is sometimes necessary that the flow of water through the respective conduits be started and stopped at different predetermined intervals. One relatively sophisticated method to perform this function is to preprogram the opening and closing of watervalves in the irrigation system. In this manner, crops may be watered on a regular, yet perhaps intermittent basis as is their need. This invention presents a new type of fluid flow control valve to accomplish this function.
This fluid flow activated valve can also be useful in other areas extrinsic from irrigation farming, although the latter is the preferred use of this apparatus. For instance, this valve may be utilized in agriculture, turf treatment (commercial and residential), landscaping, lawn and gardening applications or in a gas pipeline where it is necessary that the gas activate the opening and/or closing of a valve with the aid of a solenoid. In other contemplated environments this valve may be utilized in such small conduits as individual capillaries of a reverse osmosis system or in such large systems as sewage pipes or petroleum pipelines.
1. Field of the Invention
The field of this invention relates generally to means for resuming a fluid flow or alternatively a means for fluid flow stoppage. More specifically, the field of this invention relates to an apparatus to be situated in a conduit for the prohibiting or permitting of the flow of a fluid therethrough. The flow blockage is accomplished by a fluid flow-activiated control valve which possesses unique straight flow-through characteristics as result of the unique arrangement of its parts.
2. Prior Art
Candor compels a recognition of all known prior art. Apparatus for the stoppage of fluid flow in a conduit are generally considered valves, which are generally classified in the Patent Office Manual of Classification in Class 251. Some of the applicable areas of Class 251 relating to this application are Subclasses 44, 45, 46, 58, 30 and 298. Other areas of Class 251 and other areas of other classes may also be pertinent to this invention.
One early use of a flow stoppage means in a conduit is exemplified by Hasemann, U.S. Pat. No. 1,756,824 which discloses the use of a throttle in a conduit, the position of which is controlled by a hydraulic piston to correct small variations in pressure without creating disrupting fluctuations in pressure. The throttle is ultimately responsive to a diaphragm sensitive to a pressure in the flow conduit at a point downstream of the throttle valve. A patent issued to Gauger in 1936, U.S. Pat. No. 2,051,294, shows a spring biased fluid valve, which is closed in the at-rest position. An upper pressure chamber is provided whereby when the same is evacuated a diaphragm rises and thereby raises a valve seat opening a channel for fluid flow. However, it is noted that in this disclosure, a straight through flow pattern is not feasible nor provided; that is, the fluid must flow over and around at least two static walls before continuing traversal through the conduit. German patent No. 1,108,509 issued June 8, 1961 shows a pivoted butterfly stoppage means in communication with a pressure sensitive hydraulic cylinder responsive to the differential of an external pressure and the pressure in the fluid conduit. Another flow-activated valve, which is spring biased in the closed position is disclosed in Jensen U.S. Pat. No. 2,884,003, having a pivotally mounted butterfly valve in the passage conduit. A piston and a solenoid operate conjunctly to open and close the butterfly valve. Another flow activated diaphragm valve is disclosed in Nickells, U.S. Pat. No. 2,900,163, which also lacks a disclosure of a straight flow through of the fluid even when the solenoid acts to overcome the spring tension and thereby raises a plunger opening the valve seat for flow of fluid.
A solenoid operated pilot control valve (having a similar configuration in the flow through conduit of that of FIG. 1 of the instant drawings) is exemplified in Schnittker, U.S. Pat. No. 3,943,975. The springs of this valve are aligned so as to provide a means for fully opening the diaphragm even in periods of low differential pressure. Heretofore, the uncovered prior art has not provided a relatively low cost diaphragm responsive valve wherein the valve seat is inclined at an obtuse angle to the axis of the passage of the flow fluid in the conduit. And by inclining the valve seat relative to the axes of fluid passage, the pressure drop through the valve is minimized.
Antithetical to this position, a recent patent issued to Karbo U.S. Pat. No. 4,301,992, discloses an inclined plane valve seat that is diaphragm responsive. The valve seats to a portion of the valve body which forms an acute angle with the axial passage of fluid flow. The fluid must therefore flow over an inclined static wall in the open position as shown in FIG. 3 of Karbo. A cavity of varying pressure is provided surmounted to the valve element wherein the change in diaphragm location is sufficient to seat or unseat the valve element. It is also disclosed in Karbo that the seat element is biased in the closed position via a spring. The diaphragm of this valve is continuously under pressure during flow stoppage periods (generally between 75-95% of the time for most irrigation systems). This constant force of fluid can diminish the life expectancy of the diaphragm. And a rupture of the same could cause severe flooding and crop damage.
The above discussion of prior art is not a total compendium of knowledge relating to flow restriction devices by any means, but it is believed representative of various aspects previously disclosed in the prior art and which are exemplified generally by FIG. 1 of the instant drawings.